1. Field of the Invention
This invention an electronic apparatus with alarm function for preventing it from being misplaced, lost, and stolen, and more particularly relates to a portable telephone.
2. Description of the Related Art
Recently, portable electronic telephones have become popular devices. A flipper in which a microphone is provided is connected rotatably to a portable telephone body in which a speaker and dialing input section are provided. When a user is carrying such a portable telephone, the flipper is folded on the portable telephone body side so as not to generate a call erroneously, and when the user makes a call or receives a call, the flipper is opened for talking.
Various measures have been proposed for preventing such portable telephone from being misplaced, lost, and stolen. For example, a method that a user cannot make a call without inputting a personal identification number, and a method that a user ask the telephone service company to disconnect the telephone line are known.
Alternatively, a method that a transmitter for transmitting radio wave is built-in a portable telephone and the radio wave from the transmitter is received with a receiver has been proposed. For example, Japanese Utility Patent Laid-Open No. Hei 5-74038 discloses the combination of key-shaped transmitter and a receiver having a function to generate alarm when the portable telephone is moved outside beyond the reach of the radio wave.
However, such methods are disadvantageous as described herein under. In the case of the method of inputting a personal identification number, though the method can prevent the stolen portable telephone from being used unless the personal identification number is known, it is troublesome work to input a personal identification number each time a call is made. In the case of the method of asking the telephone service company to disconnect the telephone line, the stolen portable telephone can be used until the user asks to the telephone service company and the telephone line is actually disconnected, and if the user retrieves the stolen or lost portable telephone, the user must take a contact with the telephone service company. Further, in the case of the method that a transmitter is built-in a portable telephone, the user is required to carry at least a transmitter in addition to the portable telephone.